Anchorage in orthodontics

Abstract

Abstract Nothing particularly new has been uncovered concerning anchorage in orthodontics. Only some conceptions of its application may be questioned or need clarification. The consideration of anchorage as used in orthodontics is simplified if anchorage is thought of entirely in terms of varying degrees of resistance to the applied force. When force is applied to teeth only, it becomes necessary to evaluate carefully the type and varying degrees of resistance offered by the dental units in order to produce movement or change where desired, without producing movement or change in units where movement or change is not desired. In this connection, anchorage is a very important consideration. The problem of anchorage becomes insignificant when the main resistance to the force is extraoral. Anchorage is a less significant problem if holding arches or stabilizing plates are used as a means of reinforcement. Anchorage preparation is not essential if the, resistance is derived from extraoral appliances or from holding arches or stabilizing plates. Action of the musculature complicates the anchorage problem during treatment and retention, either directly or through the inclined planes of the teeth. The interseptal tissues also present an anchorage problem during tooth movement and retention. The use of Class II elastics may result in positioning the mandibular denture more forward in relation to the body of the mandible, regardless of the appliance used on the mandibular denture. This appears to happen more readily, however, when the lingual arch is used for anchorage than when the full-banded appliance is employed. It follows that there is more possibility of shifting the mandibular denture forward when Class II elastics are used to produce en masse distal movement of the maxillary denture than when sectional tooth movement is utilized.